What is the “Equal Weight View”?

Suppose two agents, S1 and S2, are epistemic peers regarding a proposition p: that is, suppose S1 and S2 are equally competent, equally impartial, and equally able to evaluate and assess the relevant evidence regarding p (we will call such propositions p peer-propositions for S1 and S2). After carefully reflecting on the salient evidence for p, suppose S1 and S2 discover that they disagree about p. For instance, S1 might believe the defendant is guilty, while S2 believes the defendant is innocent. Or S1 might believe that free will and determinism are incompatible, while S2 believes that the two views are compatible. More generally, S1 and S2 might assign different credences to p. Examples of peer disagreement (in each of these senses) are common in everyday life, in philosophy, and in many other disciplines. Question: How should we, if it all, revise our beliefs (regarding p) upon discovering that we disagree with someone we take to be our epistemic peer (regarding p)? Recently several authors have taken this question up, and proposed a number of different views. One currently popular and prominent view is the so-called equal weight view (EWV) of peer disagreement.1